shmem_getpage_locked() / swapin_readahead() race in 2.4.4-pre3

From: Marcelo Tosatti (marcelo@conectiva.com.br)
Date: Sat Apr 14 2001 - 10:59:40 EST


Hi,

There is a nasty race between shmem_getpage_locked() and
swapin_readahead() with the new shmem code (introduced in 2.4.3-ac3 and
merged in the main tree in 2.4.4-pre3):

shmem_getpage_locked() finds a page in the swapcache and moves it to the
pagecache as an shmem page, freeing the swapcache and the swap map entry
for this page. (which causes a BUG() in mm/shmem.c:353 since the swap
map entry is being used)

In the meanwhile, swapin_readahead() is allocating a page and adding it to
the swapcache.

I don't see any clean fix for this one.

Suggestions ?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sun Apr 15 2001 - 21:00:23 EST